Cannabis use not linked to higher risk of COPD in tobacco smokers – study

In a new study, neither current, nor lifetime cannabis use was associated with an increased risk of developing chronic obstructive pulmonary disease (COPD).

Researchers at the University of California, Los Angeles assessed the relationship between cannabis use and COPD development in adults who either smoked or formerly smoked tobacco cigarettes.

The participants were aged between 40-80-years old and either had or were at high risk for developing COPD.

COPD is a group of chronic lung conditions that cause difficulty breathing, including emphysema (damage to the air sacs in the lungs) and chronic bronchitis (long-term inflammation of the airways). 

It most often affects middle-aged or older adults who smoke and tends to get progressively worse over time, sometimes limiting the ability to carry out daily activities. 

Participants in the study were divided into groups of those who had never used cannabis, former cannabis users (not in the last 30 days) and those who currently consume (had smoked within the last 30 days).

After carrying out a number of analyses, the researchers determined that neither former nor current cannabis smoking was associated with evidence of COPD progression or its development.

While some differences between the groups were noted, these were ‘neither clinically nor statistically significant’.

However, the authors advise that the study design has some limitations and the findings should be considered ‘exploratory’. Other limitations include the variability in the delivery methods and amount of cannabis consumed by participants. 

The authors concluded: “In [this] cohort of ever-tobacco smokers of ≥20 pack-years with established COPD or at risk of developing COPD followed over an average of more than four years, a history of current and/or former smoking of marijuana of any cumulative lifetime amount was not found to be associated with a significantly deleterious impact on progression of COPD.” 

They added: “Among ever-tobacco smokers in the same cohort without COPD at enrollment, self-reported current and/or former concomitant marijuana smoking, including heavy marijuana smoking, was not found to be associated with an increased risk of subsequently developing COPD.”

The findings echo those of previous studies which also suggest cannabis inhalation is not associated with increased risks of COPD, lung cancer or other damage, in the same way that tobacco smoke is.

Commenting on the findings, deputy director of NORML in the US, Paul Armentano said: “These results are consistent with decades worth of data finding that cannabis smoke exposure is not associated with the same sort of deleterious pulmonary impact as is tobacco smoke exposure.

“They should be reassuring to cannabis consumers and to health professionals alike, and they should help to guide future policies with respect to the crafting of evidence-based public health messages and associated regulations.”

Read more about the study here

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